It is a familiar view in the philosophy of mind and action is that for a thought or attitude to constitute a reason for an action is for it to render intelligible, in the light of norms of rationality or reason, that action. However, I can make sense of your actions in this way by crediting you with attitudes that I myself do not hold. Equally, you can do this for my actions. So not all reasons for one’s actions are one’s own reasons. What more is involved in a reason’s being one’s own reason for acting?